What Soil Temperature Do Earthworms Prefer?

Earthworms require warm temperatures.

With approximately 2,700 varieties, the humble earthworm is far more than bait for the fisherman's hook. These creatures perform a vital function in improving soil structure and fertility by their composting activities. Introducing earthworms can transform poor soil if sufficient food and favorable conditions are provided.

Habitat

For earthworm activity the desirable temperature is above 40 degrees F but not exceeding 70 degrees F and a near neutral soil pH level. Extremes of these temperature ranges and less than 40 percent moisture content in soil influences all aspects of earthworm activity.

Low extremes

In soil below 40 degrees F, earthworms cease many functions including feeding. As these animals breathe through their skin, moisture is vital. However, in waterlogged soil, the oxygen is replaced by too much moisture, which drowns them.

High extremes

Unfavorable soil temperatures, especially too hot, affects a worm's ability to breed and produce cocoons to hatch offspring. Above 70 degrees F, the drier soil is tough for earthworm burrowing and their skin can dry to the point they suffocate.

References

• Colorado State University: Earthworms
• University of Illinois: Worm Facts